<p>IN THE FLORIDA EVERGLADES | U.S. Sen. Bill Nelson is blaming warm weather for an unsuccessful python hunt in the Everglades. </p><p>The Florida Democrat is among more than 1,000 people who signed up to hunt Burmese pythons during the month-long "Python Challenge."</p><p>On Thursday, Nelson sped over roughly 40 miles of sawgrass in an airboat piloted by state wildlife commissioner Ron Bergeron. They checked several isolated islands, but they came back empty-handed. </p><p>They encouraged other hunters to take advantage of colder temperatures that drive the snakes onto sunny surfaces. </p><p>Nelson championed a federal ban on the pythons.</p>